Kailway-traitic-controlling- system



L. V. LEWIS.

RAILWAY TRAFFIC CONTROLLING SYSTEM.

APPLICATION FILED APR. 28. I919.

Patented Dec. 28, 1920.

H1 Atty.

lJhll'l'E-l'l PORATION OF PENNSYLVANIA.

@Ei liCE.

rnnnsrnvanrn, ASSIGNOR TO THE swrssvann, PENNSYLVANIA, A obn- ItAILWAY-TRAIEFIC-CONTROLLING SYSTEM.

Specification of Letters Yatent.

Patented Dec. 28, 1920.

Application filed April 28, 1919. Serial No. 293,208.

To all whom it may concern:

Be it known that I, LLOYD V. LEWIS, a citizen oi the United States, residin at Edgewood Borough, in the county of fillegheny and State of Pennsylvania, have in rented certain new and useful lmprove- I ments in Railway-Tra ic-Controlling Systems, oi: which the following is a specification.

My invention relates to railway trailic controlling systems, and particularly to systems oi the type wherein alternating current or currents are supplied to the track rails, and the cars or trains are provided with governing apparatus which is controlled by such current or currents in the rails. More particularly, my invention relates to trackway circuits and apparatus whereby sys tems o l. this character may be applied to interlocking plants, that is, to plants comprising a group of railway switches and signals controlled from a central point for the purpose of dire ting trailic over any one of a number of different routes. Certain features of my invention, however, are not limited to interlocking plants, but are capable oi more general application.

In one system of the character mentioned. it has been proposed to employ the usual track circuit current, that is, the current which energizes the track relays, as one of the currents for controlling the train governing apparatus, and to supply a second or line current to the track in such manner that it 'llows in the same direction in the two rails, which current coasts with the track circuit current to control the train governing apparatus.

In the practice of my invention, the tracks of the interlocking plant are divided into track sections each of which is provided with a track circuit, and the supply of line current to each section is controlled by the track relays for each of the sections in advance. "One feature of my invention is the provision of means for controlling the supply of line current to the rails in the rear of the switch by traiiic conditions in advance on one route or the other according as the switch is in one position or the other.

T will describe one form o t trackway ap paratus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of trackway apparatus embodying my invention.

Referring to the drawing, the reference characters A and B designate two railway tracks over both of which traflic normally moves in the direction of the arrow. For example, these tracks may be two tracks of a four track railway. These tracks are ineluded within an interlocking plant which lies between the limits C and D, this distance, in practice being usually about 1500 feet. The interlocking plant comprises a crossover E leading from track A to track B, a crossover F leading from track 13 to track A, a siding G connected with track A by a switch 2, and a siding H connected with track B loy a switch. 3. The plant also includes a signal S governing trafiic into the plant on track A, and a signal S governing trallic into the plant on track B. The various switches for the crossovers and the sidings are controlled from an interlocking machine which is located in what is usually known as a tower, but the machine and tower are omitted from the drawing for the reason that they form no part of my present invention. The signals S and S are controlled in part by the interlocking machine, and in part by automatic signals R and R which govern tra'liic over tracks A and B, respectively, through this block next to the right of location 1).

The operation of signals S and S is as follows:

When the. operator of the interlocking machine desires to admit a train on track A into the interlocking limits, he moves the lever of the interlocking nachine, corresponding to signal S, whereupon it switches 4 5 and 2, are in normal positions, and if there is no train on track A within the limits C l) of the interlocking plant, and

it signal is in the proceed position, blade 6 of si; mi S moves to the full proceed position. If, on the other hand, signal it indicates stop, all other conditions remain ing the same, blade 6 moves only to the caution or inclined position. It switches 4 and t are reversed, switches S and 5 being normal, and if signal R is in the proceed or caution position, blade 6 of signal S remains in the horizontal position and blade 7 moves to the full proceed or vertical position, provided that there is no train on track A between point C and switch 4, or on track B between switch 4 and point D. If signal B is in the stop position, all other conditions being the same as just mentioned, blade 7 moves only to the caution or inclined position. If there is a train on either track A or track B within the limits referred to above, both blades of signal S remain 'in the horizontal position. If switch 4* is normal and switch 2 reversed, blade 7 A moves to the inclined position and blade 6 remains in the horizontal position, provided that there is no train between point C and switch 2.

The operation of signal S corresponds to the operation of signal S The operation of these signals is in accordance with standard practice, and, consequently, the means by which they are controlled is not illustrated in the drawing.

Each track A and B is provided with an approach section K-C located to the left of the interlocking plant, and each of these approach sections is provided with a track circuit as hereinafter explained. These ap-' proach sections are provided with approach signals Q and Q, respectively. Signal Q is controlled by a track relay T and by signal 8*, whereas signal Q is controlled by a track relay T and by signal S The operation of these signals is as follows: hen signal S indicates stop, and the approach section KC is unoccupied, the upper blade 8 of signal Q is in the inclined or caution position. Vhen the upper blade 6 of sig nal S is in either the inclined or the vertical position, blade 8 moves to the vertical position. lVhen blade 7 is in the vertical position, and the section K---C is unoccupied, blade S will be in the inclined position and blade 9 in the vertical position. course, if track section K C of track A is occupied by a car or train, both blades of signal Q assume the horizontal positions, so that the signal then indicates stop. The apparatus for controlling signal Q forms no part of my invention, and so is not shown in the drawing.

The operation of signal Q is the same as the operation of signal (2.

The track A within the interlocking limits is divided into three track sections C-J, JL, LD. Switch 4* of crossover E lies within section CJ, switch 2 of siding G lies within the limits of section JL, and switch 5 of crossover F lies within the limits of section L D.

Track B is divided into three similar track sections which include within their limits the switches 4 3 and 5 respectively.

Each track section is provided with a track circuit of the normal type comprising the rails of the section, a transformer designated by the reference character N with a suitable exponent, and a track relay designated by the reference character T with a suitable exponent. The secondary of each transformer N is connected across the rails of the track section through a reactance 54, and the primary of each of these transformers is connected with a suitable source of alternating current which is not shown in the drawing.

Each track section is provided with a transformer, designated by the reference character U with a suitable exponent, for supplying line current to the rails of the section in such manner that it lows in the same direction in the two rails. For example, referring to section L-D of track l5, the circuit for this line current is from the left-hand terminal of the secondary of transformer U through back contact 10 of track relay T to the middle point of a resistance 21 connected across the rails, thence through the two rails of section L-D in multiple to a resistance 20 likewise connected across the rails at the forward. end of the section, and from the middle point of this resistance to the right-hand terminal of the secondary of transformer U. The circuit for the line current for each section is similar to the circuit just traced. The reason for including a back contact of the track relay in this circuit is to avoid unnecessary expenditure of energy while the section is unoccupied.

Line current is supplied to the primary of each transformer U by the secondary of a transformer V whose primary is connected with a suitable source of alternating current of the same frequency as that supplied to each of the track circuit transformers N. Considering track B, the main circuit for the primary of transforn er U is from the secondary of transformer V, through wire 11, contact 12 operated by signal R wire 18, contact 14 of track relay T wire 15, contact 16 operated by switch 5, thence through the primary of transformer U and wire 17, common wire O and wire 18 to the secondary of transformer V. Contact 12 is closed when signal R indicates proceed or caution, but open when this signal indicates stop. The circuit just traced is closed at contact 16 when switch 5 is normal, but is opened at this point when the switch is reversed.

The primary of transformer U is connected in multiple with the primary of transformer U", the main circuit being from secondary of transformer V, through con tact 12 contact 14 of track relay T contact 16, wire 50. contact 51 of track relay T wire 52, contact 53 operated by switch U and common wire 0 to transformer V.-

T he circuits just traced for transformers U and U are closed when switches 3 and 5 are normal, but are open when either switch is reversed.

Considering track A, the circuit for the primary of transformer U is from the secondary of transformer V, through wires 11 and 40, contact 12, contact 14: of track relay T primary of transformer U and common wire 0 to transformer V. The circuit for the primary of transformer U is from transformer V, through contact 12, contact 14 of relay T contact 19 operated by switch 5, contact 27 of track relay T, contact 28 operated by switch 2, primary of transformer U and common wire C to transformer V. This circuit is closed only when switches 2 and 5 are normal. The main circuit for transformer U is the same as that just traced up to and including contact 28, thence through contact 29 of track relay T contact 30 operated by switch 4*, and primary of transformer U to common wire C and transformer V. This circuit is closed only when switches 4 2 and 5 are normal.

Considering the route from track B over crossover F to track A, the primaries of transformers U, U and U are provided with an auxiliary circuit from the secondary of transformer through wires 11 and 40, contact 12 contact if of relay T contact 19 reversed, wire 31, contact 16 reversed, and thence through the primaries of the said three transformers in multiple. This circuit is closed only when contacts 19 and 16 are in the opposite positions to the positions in which they are shown in the drawing, that is, when switches 5 and 5 are reversed. Under this condition it will be seen that the supply of line current to track B is governed by signal R instead of by signal R it being evident that the main circuit previously traced for the primaries of these transformers is then opened at contact 16. Considering now the route from track A over crossover E to track B, I will assume that switches 5 and 3 are normal, but'that switches 4 and 4 are reversed. Transformer U is then supplied with current through the following auxiliary circuit: From the secondary of transformer V, through contact 12 contact 1 1 of track relay T wires 15 and 15 contact 32, wire 33, contact 34: of track relay T wire 35, contact 36, contact 37 of track relay T contact 38 reversed, wire 39, contact 30 reversed, primary of transformer U and common wire C totransformer V. Under this condition, then, the supply of line current to section C-J of track A is controlled by track relays T, T and T and by signal R it being evident that the previously traced main circuit for transformer Y 2 is then opened at contact 30.

Considering now the approach section KC of track A, it will be noted that the supply of track circuit current to this section is furnished by a transformer N, through a pole changer P which is actuated by blade 6 of signal S. This pole-changer is so arranged as to reverse while this blade is moving from the vertical to the inclined position and vice versa. When the blade is in the vertical position, the track circuit current which is supplied to section K-C is of what 1 will term normal polarity, whereas when this blade is in the inclined or horizontal positions, current of reverse polarity is supplied to the track rails of this section.

The approach section for track B is suppliedwith track circuit current by a transformer N through a pole-changer P which is operated by blade 6 of signal S in the same manner as pole-changer P is operated by blade 6 Section KC of each track is provided with two resistances 20 and 21 connected across the rails adjacent the ends of the section, and with a third resistance 22 connected across the rails at a point substantially 1500 feet in the rear of point C. Line current is supplied to track r between resistances 21 and 22 by a transformer U, the supply being controlled by a back contact of track relay T. Line current is supplied to section KC of track B betweenresistances 21 and 22 from a transformer U in a similar .ianner. Line current is supplied to section KC of track A between resistances 20 and 22 by a transformer U, and this supply of current is controlled by contacts 41* and 42 operated by the blades 6* and 7 respectively, of signal S Each of these contacts is closed when the corresponding blade is in the vertical or inclined positions, but opened when the blade is in the horizontal position. Assuming that blade 6 isin the inclined or vertical position, the circuit passes from the secondary of transformer U through wire 13, contact 11, wire i,wire 45, to the middle point of resistance 20, thence through the two rails in multiple to resistance 22, and through wires 46 and 47 to thesecondary of, transformer U. Assuming now that blade 6 is in the horizontal position and that blade 7 is in the inclined or vertical position, the circuit is from the secondary of transformer U, through wire 43, contact 11*, wire 48, contact 42 wire 15, and thence as'before to the secondary of transformer U. It will'be'seen, therefore, that line current is supplied to section K-C of track A between resistances 20 and 22 when signal S gives any proceed indication, but not when this signal indicates stop.

Line current is furnished to the rails of track B between resistances 20 and 22 in section K--C by a transformer U and this,

supply is controlled by contacts 41 and 42 whose operation and function are. the same as those of the corresponding contacts 41 and a2 for track A.

Before explaining the operation of the system as a whole, it should be pointedout that the trackway apparatus here shown is intended for cooperation with train-carried governing apparatus which operates in the following manner: hen a train is on a portion of track which is supplied with line current and also with track circuit current of normal polarity, the governing apparatus permits the train to travel at high speed, such as 65 miles per hour. When the train is on a portion of track which is supplied with line current and also with track circuit current of reverse polarity, the governing apparatus prevents the train from proceeding at more than an intermediate speed, such as 35 miles per hour. the train enters a portion of track from which the supply of either track circuit current or line current has been discontinued, the governing apparatus prevents the train from proceeding at more than a low speed, such as 15 miles per hour. One form of train carried apparatus which will cooperate in this manner with the trackway circuits here shown is illustrated and described in my co-pending application filed. November 21, 1918, Serial No. 263,607, for railway traffic controlling system.

It is to be noted that the circuits are so designed that as a train approaches a stop signal, the supply of line current is cut off at a point approximately 1500 feet in the rear of the stop signal; this distance being selected for illustration as a safe braking distance for trains running 35 miles per hour or less.

The operation of the apparatus is as follows:

I will first assume that signal S is in the stop position as shown, signal Q* in the caution position as shown, and that a train moving toward the right on track A passes the point K. Track circuit current of reverse polarity is supplied to the rails of track section K-C, and line current is supplied to this section between resistances 21 and 22, but no line current is supplied between resistances 22 and 20, because the circuit for the secondary of transformer U is opened at contact 42*. The train is, therefore, reduced to the intermediate speed as soon as it passes point K, and is When reduced to the low speed after passing resistance 22.

I will now assume that switches 4, 2 and 5 are in normal positions, that signal R is in the horizontal position, and that blade 6 of signal S has been moved to the inclined position indicating proceed, prepared'to stop. Track circuit current of reverse polarity is then supplied to' section K-C, and line current is supplied to the rails of this section throughout the length of the section. A train moving toward the right on track A can then enter and pass through this approach section KC at intermediatespeed. Sincesignal R is at stop the supply of line current is cut off from section CI), so that when the train enters the interlocking limits its speed will be reduced to 15 miles per hour.

If, however, track A within the interlocking limitsv is unoccupied and signal R is in caution or proceed position, blade 6 of signal S will move to the vertical position and so will reverse pole-changer P Track circuit current of normal polarity will then be supplied to section I\C so that a train may proceed through this section at full speed. and line current will be supplied to all of the sections of track A within the interlocking limits so that the train can also pass from C to D at full speed.

I. will now assume that track A is occupied by a first train within the interlocking limits. and that it is necessary to permit a second train on this track to enter the interlocking limits. Blade 7 of signal S may then be moved to the inclined position, but blade 6 will, of course, be horizontal. The second train will then be reduced to the intermediate speed limit in section K-C. and when it passes point C it will be reduced to the low speed limit because line current will be out off due to one of the track relays T T or T* being open.

I will now assume that switches 4 and 4 have been reversed in order to divert a train from track A to track B, and that track relays T T and T are energized, and signal R indicates proceed. The several track sections of track B within the interlocking limits are then supplied. with line current in the manner shown in the drawing, and section CJ of track A is supplied with this current, but under the control of track relays T, T and T and signal R Blade 7 of signal S may then be moved to the vertical position, but blade 6 remains in the horizontal position so that track circuit current of reverse polarity is supplied to approach section K-C. A train moving toward the right on track A is, therefore, reduced to the intermediate speed upon entering this approach section, but as soon as it passes point (.3 it receives line current and also track circuit current of normal polarity. While this train is on the crossover IE, it receives no current from the track, but it can proceed through this crossover for a reason which is explained hereinafter. As soon as the train reaches track B it again receives track circuit current of normal polarity and also line current so that it is free to resume full speed.

With switches A and P reversed, if there should be a preceding train on track B between switch 2 and point D, thesupply of line current to section C-J of track A will, of course, be cut off, and so the train under consideration would be reduced to the low speed limit after passing point C. The same thing is true if signal R should be in the stop position, or if switch 3 were reversed.

IVhen switches 4 3 and 5 are normal and signal R is in the proceed or caution position, blade 6 of signal S can be moved to the vertical position, whereupon a train can proceed along track B under the same conditions as those explained hereinbefore in connection with the passage of the train over track A. If it is desired, however, to divert a train from track B to track A, switches 53 and 5 are reversed and blade 7 of signal S is moved to the inclined or vertical position. The approach section K-C of track 13 is then supplied with track circuit current of reverse polarity and the supply of line current to sections C-J, J-L and L-D of track B is governed by track relay T for track A and by signal R A train moving toward the right on track 13 is, therefore, brought down to the intermediate speed limit in the approach section K-C but it may proceed through the interlocking plant without a further reduction in speed, provided that track relays T, T and T are energized and signal R indicates caution or proceed. If track relay T is deenergized or if signal R indicates stop, the supply of line current to each section of track 13 within the limits of the interlocking plant is discontinued so that the train is brought to a stop immediately upon entering the plant.

It will be seen from the foregoing that the supply of line current to the track rails within the interlocking limits is governed bytraliic conditions in advance on the route which the train is to take.

Assuming that switch 2 is reversed and that switch 4 is normal, the supply of line current to section C-J and JL of track A is cut oil by contact 28, so that a train entering the interlocking plant on track A will be reduced to the low speed limit after passing point C.

If switch 3 is reversed, and switch 4 18 normal, a train entering the interlocking plant on track B will be reduced to the low speed limit because the supply of line current to section CJ is cut off by contact 22. Likewise if switch 8 is reversed and switches 1 and 1 are reversed, the supply of line current to section C-J of track A will be cut oif by contact 36, so that a train entering the interlocking plant on track A will be reduced to the low speed limit.

As pointed out hereinbefore, no means are provided for supplying track circuit current or line current to the rails of the crossover E. It is to be understood, however, that each train is provided with means for delaying the automatic application of the brakes, after the cessation of one or the other of the controlling currents, for an interval of time which is inversel proportional to the speed of the train. Apparatus of this character is shown and described in an application for Letters Patent of the United States, filed by Frank H. Nicholson on Dec. 21, 1918, Serial No. 267773. By virtue of this feature of the train-carried apparatus, if the engineer reduces the speed of his train to the intermediate value upon entering crossover E, the automatic application of the brakes will be delayed for a period long enough to enable the train to reach track B. If, however, the speed of the train is above the intermediate value, the automatic application of the brakes will take place before reaching track B, and so the train will be reduced to the low speed limit. It will be seen that this feature insures that the engineer will proceed througha crossover at medium speed under the penalty of incurring a brake application if the speed requirement is not observed.

The foregoing explanation concerning crossover E applies equally well to crossover F.

Although I have herein shown and de scribed only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: i

1. Railway trafiic controlling apparatus comprising two parallel tracks A and B along which traflic normally moves in the same direction, and a crossover leading from track A to track B, a track section for track A having one switch of said crossover within its limits, a source of line current for said section, and means for controlling said source by traflic conditions in advance of said crossover on track A or ontrack B according as the switches of said crossover are normal or reverse.

2. Railway trafiic controlling apparatus comprising two parallel tracks A and B along which traffic normally moves in the same direction, and a crossover leading from track A to track B, a track section for track A having one switch of said crossover with in its limits, track circuits including track relays for each track in advance of said crossover, a source of line current for said track section, and means for controlling said source by said track circuits of track A or of track B according as the switches of said crossover are normal or reverse.

Railway 'trafiic controlling apparatus comprising two parallel tracks A and 13 along which trafiic normally moves in the same direction, and a crossover leading from track A to track B, a track sertion for track A having one switch of said crossover within its limits, a signal for each track for governing trailic along thetrack in advance of said crossover, a source of line current for said section, and means for controlling said source by the signal for track A. or by the signal for track B according as the switches of said crossover are normal or reverse.

4. In combination, an interlocking system comprising two parallel tracks A and B over which trafiic normally moves in the same direction and a signal for each track "for governing traflic' through the interlock-' ing limits, an approach section for each track located in the rear of the corresponding signal, and means for the approach section of each track for supplying line current to the rails of a portion thereof when the signal for the same track indicates proceed but not when it indicates stop.

5. In combination, an interlocking system comprising a railway track; a signal for governing trafiic along said track within the interlocking limits and arranged to indicate proceed at high speed, proceed at medium speed, and stop; an approach section for said track located in the rear of said signal and means for supplying track circuit current to said approach section oi": normal polarity when said. signal indicates proceed at high speed and of reverse polarity when said signal indicates proceed at medium speed or stop.

6. In combination, a section of a railway track, a switch leading out from said section, and meansfor supplying line current to said 1 section when said switch is normal but not when 1t 18 reverse.

7. Railway trafiic controlling apparatus comprisinga main track and a second track connected therewith by a switch, means tor supplying line current to said main track in the rear of the switch, and means for con- 'trolling -thesupply of said current by traflic "conditions in advance on the main track or on the second track according as the switch is set for the main track or for the second track.

8. Railway traflic controlling apparatus comprising a main track and a second track connected therewith by a switch, means for causing line current to flow in the same direction in the two rails of the main track in the rear of said switch, and means for controlling the supply of said current by trafiic conditions in advance on the main track or on the second track according as the switch is set for the main track or for the second track.

9. In combination, a section. of railway track, three impedances connected across the rails of said section at the exit end, an intermediate point in the section, and the exit end of the section respectively, means for connecting a source of current to the middle points of the first and second impedances regardless of traflic conditions in advance of said section, and means controlled by traflic conditions in advance of said section for connecting a source of current with the middle points of the second and third of said impedances.

10. In combination, a section of: railway track, a trackway circuit including the track rails of said section in multiple from the en trance end of the section to an intermediate point in the section, means for supplying current to said circuit regardless of traffic conditions in advance of the section, a second trackway circuit including the track rails of said section in multiple from said intermediate point to the exit end of the section, and means controlled by traffic conditions in acvance of said section for supplying current to said second 'trackway circuit.

11/111 combination, a section of railway track, a track circuit for the section including a track relay, a trackway circuit for said section including the track rails in multiple from the entrance end of the section to an intermediate point in the section,'means for supplying current to said trackway circuit when. the track relay is deenergized but not when it is energized, a second trackway circuit including the track rails of said section in multiple from said intermediate point to the exit end of the section, and means controlled by traflic conditions in advance of said section for supplying current to said second track-way circuit.

12. In combination, a stretch of railway track including a section KC, a signal governing traflic along said track in -ad vance of said section, a trackway circuit including the track rails of saidsection in multiple fromtheentrance end of the-section to an intermediate point in the section, means for supplying current tosaid track- 'way circuit regardless of the indication given by said signal, a second trackway circuit for said section including the track rails of the section in multiple from said intermediate point to the exit end of the section, and means for supplying current to said second trackway circuit when said signal indicates proceed but not when it indicates stop.

18. In combination, a stretch of railway track, including a section K-C, a signal governing trafiic along said track in advance of said section, a trackway circuit including the rails of said section in series, means controlled by said signal for supplying current of one relative polarity or the other to said circuit according as said signal indicates proceed or stop, a second trackway circuit including the rails of said section in multiple from the entrance end of the section to an intermediate point in the section, means for supplying current to said second circuit regardless of the indication given by said signal, a third trackway circuit including the rails of said section in multiple from said intermediate point to the exit end of the section, and means controlled by said signal for supplying current to said third circuit when the signal indicates proceed but not when it indicates stop.

14. In combination, a section of railway track, a trackway circuit for said section including the rails of the section in series, means controlled by tra-fiic conditions in advance of said section for supplying current of one relative polarity or the other to said circuit, a second trackway circuit including the rails of said section in multiple from the entrance end of the section to an intermediate point in the section, means for supplying current to said second circuit regardless of traffic conditions in advance, a third trackway circuit including the rails of said section in multiple from said intermediate point to the exit end of the section, and means controlled by trafiic conditions in advance of said section for supplying current to said third trackway circuit.

In testimony whereof I afiix my signature in presence of two witnesses.

LLOYD V. LEWIS.

Witnesses A. HERMAN WEGNER, W. E. SMITH. 

